CN114787433A

CN114787433A - Carpet made of self-expandable PTT-containing bicomponent fibers

Info

Publication number: CN114787433A
Application number: CN202080085235.9A
Authority: CN
Inventors: D·G·马德莱内
Original assignee: DuPont Industrial Biosciences USA LLC
Current assignee: Ruixun Co ltd
Priority date: 2019-12-10
Filing date: 2020-12-08
Publication date: 2022-07-22
Also published as: EP4073301A1; KR20220104699A; AU2020402757A1; US20220290367A1; CA3152951A1; JP2023506733A; BR112022007903A2; TW202129105A; MX2022006779A; WO2021118985A1

Abstract

Disclosed herein are carpets, the face fibers of the carpets comprising bicomponent fibers comprising one component of poly (ethylene terephthalate) homopolymer or poly (ethylene terephthalate) copolymer and a second component of poly (trimethylene terephthalate) polymer or a blend of poly (trimethylene terephthalate) and poly (ethylene terephthalate) homopolymer or poly (ethylene terephthalate) copolymer, wherein the bicomponent fibers are self-bulking due to differential shrinkage. Also disclosed is an improved process for preparing a yarn to produce a carpet, the face fiber of the carpet comprising a self-bulking bicomponent fiber comprising one component of poly (ethylene terephthalate) homopolymer or poly (ethylene terephthalate) copolymer and a second component of poly (trimethylene terephthalate) or a blend of poly (trimethylene terephthalate) and poly (ethylene terephthalate) homopolymer or poly (ethylene terephthalate) copolymer.

Description

Carpet made of self-expandable PTT-containing bicomponent fibers

Technical Field

The present disclosure relates to carpets and more particularly to carpets whose face fibers comprise self-bulking bicomponent fibers comprising poly (trimethylene terephthalate) (PTT).

Background

In the manufacture of modern carpets, synthetic polymers (e.g., nylon, polyester, polypropylene) are commonly used to make fibers having a high level of bulk, which can be defined as an increase in the cover capacity or apparent volume of the fiber as compared to unexpanded or "flat" fibers. These bulked continuous fibers ("BCF") are typically monocomponent fibers made on a spinning machine with high temperature/high pressure jets and cooling cylinders specifically designed to mechanically impart a degree of bulkiness to the fibers. This process has several disadvantages. The high temperature, pressure and turbulence of the fibers in the jet can damage the fiber filaments and adversely affect the physical properties of the fibers. In addition, the need to impart bulking by the jet/cylinder process requires a reduction in fiber production speed compared to other spinning processes that do not require mechanical bulking, i.e., fully drawn yarn ("FDY") or partially oriented yarn ("POY") flat yarn.

One way to characterize textile fibers is by their amount of crimp. "crimp" refers to the waviness of the fiber and can be expressed as the number of crimps per unit length. The amount of crimp, also referred to herein as the "crimp contraction rate," can be expressed by comparing the extended length of the fiber under load to the retracted length of the fiber under no load. The amount of crimp in the fibers may be naturally occurring (e.g., wool), or imparted to the synthetic fibers in manufacture to suit the desired end use. The curl can be generated by: POY is twisted/untwisted on a false twist texturing machine using air and heat in a bulking jet (BCF) to make Draw Textured Yarn (DTY), or by differential shrinkage of side-by-side or eccentric sheath/core bicomponent fibers. A low level of crimp corresponds to a textile fiber having improved softness or bulk, and this is desirable when the opacity or coverage of the fabric is important. Alternatively, high levels of crimp result in fibers having significant levels of stretch and recovery and are valuable in apparel applications.

In carpet applications, a lower level of crimp is desirable to impart a high degree of bulk without significant stretch development. Self-crimping, high loft yarns comprising bicomponent filaments for use in fabrics are described in U.S. patent No. 7,790,282. In apparel fabrics, side-by-side and eccentric sheath/core bicomponent fiber crimp characteristics are typically maximized to provide a high level of stretch in the fibers and the resulting fabric. U.S. patent No. 6,803,102B 1, issued on 10/12/2004 to Talley et al, is an example of producing a bicomponent fiber having an asymmetric fiber cross-section and is incorporated herein in its entirety.

U.S. patent No. 6,158,204 to Talley et al, 12.12.2000, discloses a self-forming yarn made from bicomponent fibers that form a spiral crimp that locks in twist and expands. The use of such yarns in carpets and textiles is also disclosed. Various polymers are disclosed, such as poly (ethylene terephthalate) ("PET"), poly (butylene terephthalate) ("PBT"), polypropylene, nylon, and the like. However, the use of poly (trimethylene terephthalate) (PTT) is not disclosed.

U.S. Pat. Nos. 5,645,782 Howell et al, 6,109,015 Roark et al, and 6,113,825 Chuah; WO 99/19557 Scott et al; modlich, "Experience with polyester Fibers in turned arms of Heat-Set yarn tufting products," Chemievasern/Textilind. [ chemical Fibers/textile industry ]41/93, 786-94 (1991); and H.Chuah, "Corterra Poly (trimethylene terephthalate) -New Polymeric fibers for Carpets,", The Textile Institute ] Tifcon' 96(1996) (available at http:// www.shellchemicals.com/cortiera/0, 1098, 281, 00. html), all incorporated herein by reference, describes Carpets made with Poly (trimethylene terephthalate) (PTT) monocomponent fibers (homofibber) rather than bicomponent fibers.

Disclosed herein is a carpet having face fibers comprising bicomponent fibers comprising one component of poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET) and a second component of poly (trimethylene terephthalate) (PTT) or a blend of PTT and PET homopolymer or PET copolymer (co-PET), wherein the bicomponent fibers are self-bulking due to differential shrinkage, as opposed to carpets having face fibers made from mechanically bulked continuous monocomponent filaments (homofilament).

Disclosure of Invention

In a first embodiment, disclosed herein is a carpet having face fibers comprising bicomponent fibers comprising one component of poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET) and a second component of poly (trimethylene terephthalate) (PTT) polymer or a blend of PTT and PET homopolymer or PET copolymer (co-PET), wherein the bicomponent fibers are self-bulking due to differential shrinkage, in contrast to carpets having face fibers made from mechanically bulked, bulked continuous monocomponent filaments.

In a second embodiment, the bicomponent fibers may be in a side-by-side configuration or an eccentric sheath/core configuration.

In a third embodiment, the first component and the second component of the bicomponent fiber may be present in a weight ratio of 80: 20 to 20: 80.

In a fourth embodiment, the self-bulking bicomponent fibers disclosed herein have a post-heating crimp contraction as determined according to the crimp contraction method disclosed herein of equal to or less than 30%.

In a fifth embodiment, an improved process for making a yarn to produce a carpet having face fibers comprising self-bulking bicomponent fibers comprising one component of poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET) and a second component of poly (trimethylene terephthalate) (PTT) or a blend of PTT and PET homopolymer or PET copolymer (co-PET) is disclosed, comprising:

a) extruding the two components on a spinning machine capable of producing two or more separate melt streams;

b) combining the melt streams in a spinneret suitable for making bicomponent fibers;

c) quenching the self-expandable bicomponent fibers produced in step (b) in air;

d) drawing and heat setting the self-expandable bi-component fiber; and

e) the self-bulking bicomponent fiber is wound by suitable means for subsequent processing into carpet,

wherein the self-bulking bicomponent fibers eliminate the need for a mechanical bulking step.

In a sixth embodiment, the bicomponent fibers may be in a side-by-side configuration or an eccentric sheath-core configuration.

In a seventh embodiment, the first component and the second component of the bicomponent fiber may be arranged in a weight ratio of 80: 20 to 20: 80.

In an eighth embodiment, the self-bulking bicomponent fibers disclosed herein have a post-heating crimp contraction as determined according to the crimp contraction method disclosed herein of equal to or less than 30%.

Detailed Description

All patents, patent applications, and publications cited are incorporated by reference herein in their entirety.

As used herein, the terms "embodiment" or "disclosed" are not intended to be limiting, but generally apply to any embodiment defined in the claims or described herein. These terms are used interchangeably herein.

In this disclosure, a number of terms and abbreviations are used. Unless otherwise specifically noted, the following definitions apply.

The articles "a/an" and "the" preceding an element or component are intended to be non-limiting with respect to the number of instances (i.e., occurrences) of the element or component. Thus, "a" and "the" should be understood to include one or at least one and singular forms of an element or component also include the plural unless the number clearly indicates the singular.

The term "comprising" means the presence of the stated features, integers, steps or components as referred to in the claims, but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. The term "comprising" is intended to include embodiments encompassed by the terms "consisting essentially of … …" and "consisting of … …". Similarly, the term "consisting essentially of … …" is intended to include embodiments encompassed by the term "consisting of … …".

Where present, all ranges are inclusive and combinable. For example, when a range of "1 to 5" is recited, the recited range should be interpreted to include ranges of "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. As used herein in connection with numerical values, the term "about" refers to a range of +/-0.5 of the numerical value, unless the term is otherwise specifically defined in context. For example, the phrase "a pH of about 6" means a pH of 5.5 to 6.5 unless the pH is otherwise specifically defined. Every maximum numerical limitation given throughout this specification is intended to include every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this specification will include every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this specification will include every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein.

As used herein, the term "bicomponent fiber" refers to a fiber comprising two different polymer components, which may consist of different polymer types, the same polymer type but with different intrinsic viscosities, or a blend of two or more polymers, extruded from the same spinneret with both polymers in the same filament. Bicomponent fibers may also be referred to as composite fibers, and these terms may be used interchangeably.

The term "BCF" refers to bulked or bulked continuous monocomponent filaments. It is essentially a long continuous fiber bundle used to make carpet. The terms "bulking" and "puffing" are used interchangeably herein.

As used herein, the term "carpet" refers to a floor covering comprised of pile yarns or fibers and a backing system. They may be tufted or woven. As used herein, the term "carpet" includes full house carpet, modular carpet, floor mats, and mats for vehicle and building entrances, such as those designed to capture mud under the feet.

The term "face" refers to the side of the carpet containing the tufted or woven yarns.

As used herein, the term "face fiber" refers to the fiber content of the carpet, including the fiber content that is visible to an observer. The face fibers are made primarily of yarns, and these yarns may be patterned in cut, loop, cut and loop or any number of patterns known to those skilled in the art.

The term "copolymer" refers to a polymer composed of a combination of more than one monomer. The copolymer may form the basis of some man-made fibres.

The term "crimp" refers to the waviness of a fiber, expressed as the number of crimps per unit length. "crimping" is the process of imparting crimp to a filament yarn.

The term "crimp contraction" is a measure of the crimp of a fiber and refers to the contraction in length of a yarn from a fully extended state (i.e., where the filaments are substantially straight). This is due to the formation of crimp in the individual filaments under specific crimp development conditions. It is expressed as a percentage of the extended length. Crimp contraction can be measured before and/or after the fiber is treated (e.g., by heating) to partially or fully develop crimp; typically, the crimp shrinkage after heating is more interesting and informative because it includes the crimp exhibited by heating. Unless otherwise indicated, the crimp contraction value disclosed herein is the crimp contraction value after heating (Cca).

The term "denier" is a measure of the weight per unit length of any linear material.

The term "fiber" refers to the unit of matter, either natural or synthetic, that forms the basic element of fabrics and other textile structures. Characterized by having a length at least 1000 times its diameter or width. Typically, textile fibers are units that can be spun into yarns or made into fabrics by various methods including weaving, knitting, braiding, felting, and twisting. The fibers are characterized by their denier (grams by weight per 9000 meters of fiber) and the number of filaments contained in the fiber.

"filament" refers to a fine wire or continuous strand of fibers. There are two types of filaments: single-filament (mono-filament) and multi-filament (multi-filament). The filaments are characterized by their denier per filament ("dpf").

The term "monocomponent filament" means that the filament is made of one polymer type.

"staple fibers" refers to natural fibers or lengths cut from filaments.

The term "intrinsic viscosity" ("IV") refers to the ratio of the specific viscosity of a solution of known concentration to the concentration of solute extrapolated to zero concentration.

The term "tufting" refers to the process of manufacturing a textile (such as a carpet) on a dedicated multi-needle machine. A "tuft" is a cluster of soft yarns that is drawn through the fabric and protrudes from the surface in the form of cut yarns or loops. The cut or uncut loops form the face of the tufted or woven carpet.

The term "yarn" refers to a collection of individual filaments, either individually or plied together with another collection of filaments. The terms "fiber" and "yarn" are used interchangeably herein.

The term "quench" refers to rapid cooling in water, oil, or air to achieve certain physical or material properties.

The term "poly (ethylene terephthalate)" or PET means a polymer derived substantially only from ethylene glycol and terephthalic acid (or equivalent, such as dimethyl terephthalate), and is also referred to as a poly (ethylene terephthalate) homopolymer. As used herein, the term "poly (ethylene terephthalate) copolymer" or "co-PET" refers to a polymer comprising repeat units derived from ethylene glycol and terephthalic acid (or equivalents) and also containing at least one additional unit derived from an additional monomer, such as isophthalic acid (IPA) or Cyclohexanedimethanol (CHDM). The poly (ethylene terephthalate) copolymer can contain from about 1 mole% to about 30 mole% of the additional monomer, for example from about 1 mole% to about 15 mole% of the additional monomer.

The term "poly (butylene terephthalate)" or PBT means a polymer derived substantially only from 1, 4-butanediol and terephthalic acid, and is also referred to as a poly (butylene terephthalate) homopolymer. As used herein, the term "poly (butylene terephthalate) copolymer" refers to a polymer comprising repeat units derived from 1, 4-butanediol and terephthalic acid and also containing at least one additional unit derived from an additional monomer, such as a comonomer of the PTT copolymer disclosed herein.

The term "poly (trimethylene terephthalate)" or PTT refers to a polyester made by polymerizing 1, 3-propanediol with terephthalic acid. It is characterized by high elastic recovery and resilience. PTT is known to provide stain resistance, static resistance, and improved dyeability. The term "poly (trimethylene terephthalate) homopolymer" means a polymer substantially only of 1, 3-propanediol and terephthalic acid (or equivalent). The term "poly (trimethylene terephthalate)" also includes PTT copolymers, which means polymers comprising repeat units derived from 1, 3-propanediol and terephthalic acid (or equivalent) and also containing at least one additional unit derived from an additional monomer. Examples of PTT copolymers include copolyesters prepared using 3 or more reactants each having two ester-forming groups. For example, co- (trimethylene terephthalate) can be used, wherein the comonomer used to prepare the copolyester is selected from the group consisting of: linear, cyclic and branched aliphatic dicarboxylic acids having 4 to 12 carbon atoms (e.g., succinic acid, glutaric acid, adipic acid, dodecanedioic acid, and 1, 4-cyclohexanedicarboxylic acid); aromatic dicarboxylic acids other than terephthalic acid and having 8 to 12 carbon atoms (e.g., isophthalic acid and 2, 6-naphthalenedicarboxylic acid); linear, cyclic and branched aliphatic diols having 2 to 8 carbon atoms (other than 1, 3-propanediol, such as ethylene glycol, 1, 2-propanediol, 1, 4-butanediol, 3-methyl-1, 5-pentanediol, 2-dimethyl-1, 3-propanediol, 2-methyl-1, 3-propanediol and 1, 4-cyclohexanediol); and aliphatic and aromatic ether glycols having 4 to 10 carbon atoms (e.g., hydroquinone bis (2-hydroxyethyl) ether or poly (ethylene ether) glycols having a molecular weight of less than about 460, including diethylene ether glycol). The comonomer is typically present in the copolyester at a level of from about 0.5 mole% to about 15 mole%, and may be present in an amount up to about 30 mole%.

The term "Triexta" refers to the generic name of the sub-class PTT of polyesters. The terms Triexta and PTT may be used interchangeably herein.

The poly (trimethylene terephthalate) typically has an intrinsic viscosity of about 0.5 deciliters per gram (d1/g) or more, and typically about 2dl/g or less. The poly (trimethylene terephthalate) preferably has an intrinsic viscosity of about 0.7dl/g or more, more preferably 0.8dl/g or more, even more preferably 0.9dl/g or more, and typically the intrinsic viscosity is about 1.5dl/g or less, preferably 1.4dl/g or less, and currently available commercial products have an intrinsic viscosity of 1.2dl/g or less. Poly (trimethylene terephthalate) can be trademarked

Commercially available from dupont, Wilmington, DE, e.i. du Pont DE Nemours and Company, Wilmington, delavay.

Carpets made from poly (trimethylene terephthalate) monocomponent fibers and their manufacture, as well as the manufacture of these fibers and fibers, are described in U.S. Pat. nos. 5,645,782 Howell et al, 6,109,015 Roark et al, and 6,113,825 Chuah; U.S. patent nos. 6,740,276, 6,576,340, and 6,723,799; WO 99/19557 Scott et al; modlich, "Experience with polyester Fibers in turned arms of Heat-Set yarn tufting products," Chemievasern/Textilind. [ chemical Fibers/textile industry ]41/93, 786-94 (1991); and h.chuah, "Corterra Poly (trimethylene terephthalate) -New Polymeric fibers for Carpets," The Textile Institute "Tifcon' 96(1996), all references incorporated herein by reference. The staple fibers are mainly used for making household carpets. BCF yarns are used to make all types of carpets and are generally preferred for carpets.

Typically, bicomponent fibers containing PTT are used to make fabrics and garments with durable stretch properties. In contrast, such tensile properties are not required in the manufacture of carpet. In contrast, the fibers used to make carpets are typically mechanically bulked to provide a high level of bulk; such fibers are typically referred to as "BCF" fibers.

Disclosed herein is a carpet having face fibers comprising bicomponent fibers comprising one component of poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET) and a second component of poly (trimethylene terephthalate) (PTT) or a blend of PTT and PET homopolymer or PET copolymer (co-PET), wherein the bicomponent fibers are self-bulking due to differential shrinkage, as opposed to carpets having face fibers made from mechanically bulked continuous monocomponent filaments.

Also disclosed is an improved process for making a yarn to produce a carpet having face fibers comprising self-bulking continuous fibers comprising one component of poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET) and a second component of poly (trimethylene terephthalate) (PTT) or a blend of PTT and PET homopolymer or PET copolymer (co-PET), the process comprising:

d) stretching and heat-setting the self-expandable bicomponent fibers; and

e) the self-bulking bicomponent fiber is wound up by suitable means for subsequent processing into carpet.

The bicomponent fibers described herein may be in a side-by-side ("S/S") or eccentric sheath-core ("S/C") configuration. Bicomponent fibers can be made into various cross-sectional shapes, such as round, triangular, trilobal, fan-shaped, or other shapes, by using a spinneret specific to each shape, for example, as disclosed in U.S. patent No. 6,803,102, which is incorporated herein by reference in its entirety.

Typically, the fibers used in carpets are monocomponent fibers that are subjected to a mechanical bulking step in the manufacturing process. In contrast, carpets described herein whose face fibers comprise self-bulking continuous fibers comprising bicomponent fibers comprising poly (trimethylene terephthalate) are self-bulking due to differential shrinkage.

As noted above, one of the components of the self-bulking bicomponent fiber is PTT or a blend of PTT with PET or with co-PET. PTT is very effective in providing curl due to its unique shrinkage characteristics compared to other commercially available polyesters. Another component of the self-bulking bicomponent fiber is PET or co-PET, and since its shrinkage is minimal compared to PTT, this combination of components allows for the greatest shrinkage differential and thus curl development. In contrast, poly (butylene terephthalate) (PBT) is less preferred as a component for use with PTT or PTT/PET blends to make self-expanding bicomponent fibers because PBT, PTT and PTT/PET blends will shrink significantly, resulting in lower differential shrinkage between the two components and therefore lower crimp development of the resulting bicomponent fiber. For example, a bicomponent fiber comprising PTT and PET as two components will provide a higher degree of bulking than a bicomponent fiber comprising PBT and PET as two components or a bicomponent fiber comprising two different PET's each having a different Intrinsic Viscosity (IV) as two components when the weight ratio of the polymers in the side-by-side or eccentric sheath/core self-bulking bicomponent fiber is equal.

Nylon polymers, including nylon 6 and nylon 66, may also be used as the first component of the self-expandable bicomponent fibers; however, nylon polymers generally do not have sufficient adhesion to the polyester as the second component and may split and split when subjected to stress. Accordingly, bicomponent fibers comprising nylon and polyester may not be the best choice for carpet yarns.

Bicomponent PET or co-PET and blends of PTT or PTT with PET or coPET may be present in the self-bulking bicomponent fiber in a weight ratio of from 80: 20 to 20: 80. For example, the weight ratio of the first component to the second component can be 80: 20, 75: 25, 70: 30, 65: 35, 60: 40, 55: 45, 50: 50, 45: 55, 40: 60, 35: 65, 30: 70, 25: 75, 20: 80, or any ratio within this range. In one embodiment, the weight ratio of the first component to the second component is about 50: 50.

For use in carpets, the self-bulking bicomponent fibers have a post-heat crimp shrinkage value of 30% or less. The crimp contraction after heating can be measured by the crimp contraction method disclosed in the examples section below. There are several ways in which the two components of a bicomponent fiber can be adjusted to achieve a desired crimp contraction after heating of 30% or less in the resulting bicomponent fiber. One option is to adjust the Intrinsic Viscosity (IV) of each component relative to the other. For example, if the difference in IV between the two components of a bicomponent fiber is large, a high level of differential shrinkage between the two components can occur, resulting in high crimp values and fiber tensile properties that are not suitable for making carpet. In contrast, if the difference in IV between the two components is too small, no substantial difference in shrinkage occurs between the two components, resulting in little bulking.

Another way to produce bicomponent fibers with a preferred level of crimp is to vary the weight ratio of the two components. If the bicomponent fiber contains a significant proportion of PTT, the resulting fiber can have a high crimp value and fiber stretch. Conversely, very low amounts of PTT in volume ratio may not provide sufficient degree of expansion or crimp contraction upon heating to achieve the desired level.

A third way to produce bicomponent fibers with preferred crimp levels is to use a PET/PTT blend as one component in a fixed ratio (e.g., 50/50 weight ratio for PTT and PET) and PET as the second component. It has been found that blending PET with PTT in one component can be used to improve the high shrinkage characteristics of PTT alone. When two components are made from one component comprising a blend of PTT and PET and the second component is PET, then fibers having equal weight ratios (e.g., 50/50w/w component 1 to component 2) can be prepared to provide the desired level of crimp, i.e., a crimp shrinkage after heating of 30% or less. In some spinneret designs, it may be desirable to produce bicomponent fibers having nearly equal weight ratios of the two components, and blending PET with PTT is one way to achieve this result.

Alternatively, useful bicomponent fibers as disclosed herein can be prepared by varying the composition of the PTT/PET blend in one component of the bicomponent fiber where the second component is PET or co-PET. This process can be used to make useful bicomponent fibers where high levels of PET may be required. In summary, varying the polymer type, IV, weight ratios, and blend composition are all techniques by which self-expanding bicomponent fibers can be designed to achieve target crimp values that result in the desired degree of carpet expansion. Changing the relative speed of the rolls and/or winder during fiber production can also affect crimp shrinkage.

One benefit of PTT in the self-expanding bicomponent fiber disclosed herein is that it provides a high level of shrinkage compared to PET. Relatively small amounts of PTT may be used as one component of the self-bulking bicomponent fiber to produce a bicomponent fiber having the desired degree of bulking. However, too high a level of PTT content in the bicomponent fiber may result in too high a level of stretch to be useful in carpet yarn and would be more suitable for apparel applications.

Various additives may be added to one or both polymers. These additives include, but are not limited to, lubricants, nucleating agents, antioxidants, ultraviolet stabilizers, pigments, dyes, antistatic agents, clay agents, stain agents, antimicrobial agents, and flame retardants.

For use in carpets, the self-bulking bicomponent fibers disclosed herein can have a denier of from about 300 to about 1400 grams per denier. Useful denier per filament may be from about 2 to about 20.

In one embodiment of a carpet wherein the bicomponent fibers are self-bulking due to differential shrinkage, the one component comprises PTT having an intrinsic viscosity of about 0.9dL/g to about 1.25dL/g and the second component comprises PET having an intrinsic viscosity of about 0.64dL/g, and the weight ratio of the two components is about 50/50.

In another embodiment, one component comprises PTT having an intrinsic viscosity of about 0.9dL/g to about 1.0dL/g and the second component comprises PET having an intrinsic viscosity of about 0.5dL/g, and the weight ratio of the two components is about 20/80 to about 30/70.

In another embodiment, one component comprises an 50/50 weight/weight blend of PTT and co-PET, wherein PTT has an intrinsic viscosity of about 0.9dL/g to about 1.0dL/g and co-PET has an intrinsic viscosity of about 0.75dL/g to about 0.85dL/g, and the second component comprises PET having an intrinsic viscosity of about 0.5dL/g, and the weight ratio of the two components is about 70/30 to about 30/70.

In another embodiment, one component comprises a blend of PTT and Co-PET, wherein PTT has an intrinsic viscosity of about 0.9dL/g to about 1.0dL/g and Co-PET has an intrinsic viscosity of about 0.75dL/g to about 0.85dL/g, and wherein the weight ratio of PTT and Co-PET in the blend is about 10/90 to about 90/10, and the second component comprises PET having an intrinsic viscosity of about 0.5dL/g, and the weight ratio of the two components is about 50/50.

The fibers can be made by delivering the polymer to the spinneret in the desired volume or weight ratio. Although any conventional multicomponent spinning technique can be used, exemplary spinning equipment and processes for making bicomponent fibers are described in U.S. Pat. No. 5,162,074 to Hills.

The self-bulking bicomponent fibers disclosed herein can be used with all other types of synthetic and natural fibers used to make carpets. Carpets can be made by mechanical or manual tufting, weaving, and hand knotting. Examples include 1) broadloom carpets (also known as full house carpets), wherein tufted carpets are made in long continuous lengths several meters wide for home and commercial applications; 2) modular carpet tiles, produced in squares of various sizes to facilitate installation; 3) a household rug; and 4) mats for vehicle and building entrances designed to capture soil beneath the feet prior to entering the building.

Any method known in the art for making carpets from fibers may be used to make the carpets described herein. Typically, the self-bulking bicomponent fibers disclosed herein can be used in the same carpet making process using other synthetic and natural fibers. Bicomponent fibers may be used in carpet manufacture by themselves (i.e., as "single" yarns), or plied together with more of the same bicomponent fiber or other fiber type (e.g., nylon, polypropylene, polyester) to increase denier. Optionally, the single and plied fibers may be entangled with air jets prior to plying and may also be heat-set by machines specifically designed to heat-set the physical characteristics of the single and tufted yarns. An example of a heat setter suitable for this purpose is one made of

(Milus, France, Muhouse). Whether the bicomponent fibers are optionally air-entangled, plied, or heat-set, the fibers can be tufted into a standard nonwoven or woven backing sheet typical of the carpet industry.The face fiber loops in the tufted carpet can be cut to provide a cut loop carpet. After tufting, an adhesive is often applied to the back side of the carpet (i.e., the side opposite the face fibers) to hold the tufts in place. Additional backing layers may also be added to the back of the carpet. The adhesive layer may contain fillers or flame retardants depending on the particular carpet end use. The carpet can then be dyed by standard processes common to the carpet manufacturing industry; alternatively, pigments may be added to the bicomponent fibers and/or the companion fibers during fiber extrusion to impart color to the finished fabric. In addition, the face yarn may be treated with materials designed to impart fire resistance, antistatic properties, or stain and soil resistance. The finished carpet is often dried to remove residual water from the dyeing process.

The above-described manufacturing process is a typical process for wide tufted carpets. Variations on this process known in the industry can be used in the production of carpet tiles, modular carpet tiles, and automotive mats.

One feature of the bicomponent fibers disclosed herein is that the crimp and bulkiness is exhibited by raising the temperature of the fibers to at least 75 ℃ but less than 200 ℃. During the optional heat-setting, dyeing and drying steps, the bicomponent fiber will be subjected to this temperature range in the standard process of carpet manufacture. Alternatively, the carpet can be subjected to a separate heating step to exhibit the degree of bulkiness, or the bicomponent fibers (single or plied) can be heat treated to exhibit the degree of bulkiness.

The face fibers comprising the bicomponent fibers may have a circular or non-circular cross-section, such as a trilobal shape. It should have a crimp contraction after heating equal to or lower than 30%.

An advantage of the carpet disclosed herein is that because the bicomponent fiber is self-bulking due to its differential shrinkage, no mechanical bulking of the yarn used to make the carpet is required. In contrast, carpet yarns made from bulked continuous monocomponent filaments will require mechanical bulking because it cannot undergo differential shrinkage. In other words, by using bicomponent fibers with differential shrinkage to make carpet, the step of mechanically bulking the continuous monocomponent filament is eliminated.

Optionally, carpets whose face fibers comprise the self-bulking bicomponent fibers disclosed herein may further comprise at least one additional fiber. The at least one additional fiber may be plied with the self-bulking bicomponent fiber to increase denier (for example), or may be used as an additional carpet yarn when tufting a carpet. The at least one additional fiber may be selected from the group consisting of bulked continuous filaments (i.e., monocomponent filaments), synthetic staple fibers, and natural fibers. In one embodiment, the at least one additional fiber is bulked continuous filament and the bulked continuous filament comprises nylon, polypropylene, or polyester. In another embodiment, the at least one additional fiber is a synthetic staple fiber, and the synthetic staple fiber comprises nylon or polyester. In another embodiment, the at least one additional fiber is a natural fiber, and the natural fiber comprises wool, silk, or cotton.

Non-limiting examples of embodiments disclosed herein include:

1. a carpet having a face fiber comprising a bicomponent fiber comprising one component of poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET) and a second component of poly (trimethylene terephthalate) (PTT) or a blend of poly (trimethylene terephthalate) (PTT) and poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET), wherein the bicomponent fiber is self-bulking due to differential shrinkage, as opposed to a carpet having a face fiber made from mechanically bulked continuous monocomponent filaments.

2. The carpet of example 1 wherein the bicomponent fibers may be in a side-by-side configuration or an eccentric sheath-core configuration.

3. A carpet according to example 1 or 2 wherein the first and second components of the bicomponent fibres are present in a weight ratio of from 80: 20 to 20: 80.

4. The carpet of examples 1, 2 or 3 wherein the bicomponent fiber has a post-heating crimp contraction as determined according to the crimp contraction method of equal to or less than 30%.

5. The carpet of examples 1, 2, 3 or 4, wherein the face fibers further comprise at least one additional fiber selected from the group consisting of: bulked continuous filaments, synthetic staple fibers, and natural fibers.

6. The carpet of embodiment 5, wherein the at least one additional fiber is bulked continuous filament and the bulked continuous filament comprises nylon, polypropylene, or polyester.

7. The carpet of embodiment 5, wherein the at least one additional fiber is a synthetic staple fiber and the synthetic staple fiber comprises nylon or polyester.

8. The carpet of embodiment 5, wherein the at least one additional fiber is a natural fiber, and the natural fiber comprises wool, silk, or cotton.

9. An improved process for making a yarn to produce a carpet having face fibers comprising a self-bulking bicomponent fiber comprising one component of a poly (ethylene terephthalate) homopolymer or poly (ethylene terephthalate) copolymer and a second component of a blend of poly (trimethylene terephthalate) or poly (trimethylene terephthalate) and poly (ethylene terephthalate) homopolymer or poly (ethylene terephthalate) copolymer, the process comprising:

c) quenching the self-bulking bicomponent fibers produced in step (b) in air;

d) stretching and heat-setting the self-expandable bicomponent fibers; and

e) the self-bulking bicomponent fiber is wound up by suitable means for subsequent processing into carpet,

10. The improved process of example 9 wherein the bicomponent fibers can be in a side-by-side configuration or an eccentric sheath-core configuration.

11. The improved process of example 9 or 10 wherein the first component and the second component of the bicomponent fiber are present in a weight ratio of from 80: 20 to 20: 80.

12. The improved process of examples 9, 10 or 11 wherein the bicomponent fiber has a post-heating crimp contraction as determined according to the crimp contraction process of equal to or less than 30%.

Examples of the invention

The disclosure is further defined in the examples below. It should be understood that these examples, while indicating certain embodiments, are given by way of illustration only. From the above discussion and the examples, one skilled in the art can ascertain the essential characteristics of this disclosure, and without departing from the spirit and scope thereof, can make various changes and modifications to adapt it to various usages and conditions.

As used herein, "comp.ex." means a comparative example; "ex." means an example; "No." means a number; "%" means percent or percent; "wt%" means weight percent; "IV" means intrinsic viscosity; "dL/g" is deciliter per gram; "g" is g; "mg" is mg; "° c" means degrees celsius; "° F" means fahrenheit; "temp" means temperature; "min" is minutes; "h" is hours; "sec" is seconds; "lb" is pounds; "kg" is kg; "mm" is millimeters; "m" is rice; "gpl" is grams/liter; "m/min" is meters/min; "mol" is a mole; "kg" is kilograms; "ppm" is parts per million; "wt" is weight; "dpf" is denier per filament; "gpd" or "g/d" is grams/denier; "dtex" means dtex; "dN/tex" means decinewtons/tex; "mL" means milliliters; "IV" means intrinsic viscosity;

all materials were used as received unless otherwise indicated.

Measurement of crimp shrinkage after heating (% CCa) -crimp shrinkage method

The post heating crimp shrinkage (Cca) value was determined according to the methods described herein. The fibers of each example and comparative example were independently formed into skeins of about 5000+/-5 total denier (5550dtex) using a hank winder at a tension of about 0.1gpd (0.09 dN/tex). The skein was then halved in length by folding it in half to accommodate the inside of the oven used for heat setting. The folded skein was hung on a hook at its middle portion and conditioned at 70 +/-1F (21+/-1℃) and 65 +/-2% relative humidity for at least 16 hours. The folded skein was then suspended substantially vertically by hooks from a frame at its middle part and a weight of 1.5mg/den (1.35mg/dtex) was suspended at the bottom of the skein by two loops of the folded skein. The weighted skein was then heated in an oven at 250F (121℃) for 5min, after which the shelves and skein were removed and allowed to cool for 5 minutes, and then conditioned for at least 2 hours at 70F +/-1F (21+/-1℃) and 65% +/-2% relative humidity, with a 1.5mg/den weight left on the skein for the remainder of the test. The length of the skein was measured to within 1mm and recorded as "Ca". Next, a 1000g weight was suspended from the bottom of the skein, allowed to equilibrate, and the length of the skein was measured within 1mm and recorded as "La". The crimp contraction rate after heating "CCa" value (%) was calculated according to the following equation:

％CCa＝100x(La-Ca)/La

determination of intrinsic viscosity

Intrinsic Viscosity (IV) was determined using a viscotech Y501C forced flow viscometer (Malvern Corporation, Houston Texas, USA). A0.15 g sample was weighed into a 40mL glass vial containing 30mL of solvent (phenol/1, 1, 2, 2-tetrachloroethane (60/40 weight percent)) and a stir bar. The sample was then placed in a heated block (heat block) preheated at 100 ℃, heated and stirred for 30 minutes, removed from the block and cooled for 30 to 45 minutes before being placed in the viscometer's autosampler stand. The samples were then analyzed by ASTM Method D5225-92(Standard Test Method for Measuring Solution Viscosity for polymers With A Differential Viscometer).

Preparation of polymers

Two grades of PTT homopolymer particles were obtained from dupont corporation of Wilmington, tera, USA (E.I du Pont de Nemours and Company, Wilmington, Delaware USA). One grade had an IV of 1.02dL/g and the second grade had an IV of 0.96 dL/g. PET homopolymer pellets were obtained from china Petrochemical Shanghai Petrochemical Company, ltd. Shanghai, PRC, Shanghai, china, and had an IV of 0.50 dl/g. From dupont

PET homopolymer pellets were obtained and had an IV of 0.64 dl/g. Particles of Co-PET copolymer (containing 1.9 mol% isophthalic acid) having an IV of 0.82dl/g were obtained from southern Asia Plastics industries, Inc. (Nanya Plastics Corporation, Livingston New Jersey, USA) of Riwenston, N.J..

A polymer blend composition was made from a physical blend of 0.96IV PTT particles and 0.82IV PET copolymer particles ("salt and pepper" (S & P) blend) prior to extrusion. During spinning, these particle blends are intimately mixed during the extrusion process. Alternatively, in some examples, PTT and PET copolymer pellets are compounded with a twin screw extruder, pelletized and used directly during spinning without the need to make a salt and pepper blend.

In preparation for melt spinning, the pellets were dried under nitrogen in a vacuum oven under 25 inches of mercury vacuum at a temperature of 120 ℃ for 15 hours. The dried pellets were transferred directly to the nitrogen purged feed hopper of the spinning machine.

Preparation of fibres

The two components of the bicomponent fiber are melt spun using processes and equipment generally suitable for spinning of side-by-side and eccentric sheath/core bicomponent fibers, for example, as disclosed in U.S. patent No. 6,641,916B1, U.S. patent No. 6,803,102, and U.S. patent No. 7,615,173B 2, which are incorporated herein by reference.

In spinning the bicomponent fibers of the examples, the polymers were melted in a pair of Verner and Praderlel (Werner & Pfleiderer) co-rotating 28mm twin screw extruders having capacities of 0.5 to 40 lbs/hr (0.23 to 18.1 kg/hr). One extruder (referred to herein as East extruder) was used to melt the PET homopolymer (0.50IV and 0.64IV) pellets and a second extruder (referred to herein as West extruder) was used to melt 1) the individual PTT pellets; 2) salts of PTT particles and co-PET copolymer particles and pepper ("S & P") blends; or 3) compounded PTT/co-PET pellets. The temperatures of the West extruder, spinning block and East extruder are listed in the examples. Each extruder feeds a spinning module containing a concave spinneret. The spinneret used was a post-coalescence, side-by-side bicomponent spinneret with thirty-four pairs of capillaries arranged in a circle, with an internal angle between each pair of capillaries of 30 degrees, a capillary diameter of 0.64mm, and a capillary length of 4.24 mm.

The bicomponent filaments exiting the spinneret were cooled by cross-flow quench air at nominally 20 ℃ and 0.5mm/s face velocity. The filaments are then advanced to dual feed rolls operating at about 800 to 1200 meters per minute depending on the draw ratio. A finish applicator is used to apply a lubricant to the filament bundle between the spinneret and the feed roll. To affect stretching, the feed rolls are typically heated to 70 ℃. The filament bundle is then accelerated to an annealing roller which runs at a speed of about 3000 to 3600m/min depending on the desired draw ratio and the annealing roller temperature is typically 170 ℃. The annealed bicomponent fiber was then advanced to two sets of double relax (letdown) rolls running at room temperature before winding on a Barmag SW 6600 winder. The fibers have a snowman (oval) cross-sectional shape.

Example 1

Variation of Intrinsic Viscosity (IV) of PTT

Example 1 illustrates the use of PTT particles having different IVs to produce bicomponent fibers having desired values of crimp contraction after heating (CCa). The PTT particles used to prepare the fibers had an IV of 1.25dl/g (1a) or 1.02dl/g (1 b). The IV of the PET pellets was 0.64dl/g in both cases. For each example, the weight ratio of PTT to PET was 50/50. Example 1-a is a 115 denier 34 filament fiber. Example 1-b is a 75 denier 34 filament fiber.

TABLE 1 Process conditions and crimp shrinkage for examples 1a and 1b

Example 2

Variation of PTT/PET weight ratio

Example 2 shows how changing the weight ratio of the PTT and PET components in the bicomponent fiber changes the crimp contraction after heating (CCa). The bicomponent fibers were 75 denier, 34 filaments. In table 2, comparative examples A, B and C exhibited high CCa levels, i.e., greater than 30%, and were more suitable for apparel products requiring stretch and recovery. Examples 2a, 2b and 2c show process conditions that result in the production of high loft bicomponent fibers having a crimp contraction after heating of 30% or less, which fibers are suitable for use in making carpet. For comparative example A, the winder speed was 3495 m/min; and for comparative examples B and C and examples 2a, 2B and 2C, the winder speed was 3500 m/min.

TABLE 2 Process conditions and crimp contraction for comparative examples A, B and C and examples 2a, 2b, and 2C

Note that:

at 70 deg.C

At room temperature

Example 3

Variation in weight ratio between two components with fixed PTT/co-PET blend as one component

Table 3 shows how one component of the bicomponent was prepared from an 50/50 blend of PTT and co-PET, and how the second component was prepared from PET. In examples 3a to 3e, an 50/50 weight percent "salt and pepper" blend of 0.96IV dl/g PTT particles and 0.82IV dl/g co-PET particles was mixed together until the particles were randomly dispersed. After drying, the pellet mixture was fed to a West extruder. The dried 0.50IV PET homopolymer pellets were fed to an East extruder. Bicomponent fibers were then prepared with a first component comprising an 50/50 weight blend of PTT/co-PET as described above and a second component that was PET, with the weight ratio between the two components varying. For example, example 3a was prepared at a weight ratio of 70/30 between the first component (i.e., 50/50 PTT/co-PET blend) and the second component (i.e., PET). In the remaining examples in table 3, the polymer remains unchanged and only the weight ratio between the two components is changed. For all these examples, the winder speed was 3500 m/min.

TABLE 3 example 3 Process conditions and crimp shrinkage obtained

Example 4

Variation of the PTT/co-PET blending ratio in one component with a fixed weight ratio between the two components

Table 4 shows how one component of the bicomponent was made with a blend of PTT and co-PET, and how the second component was made from PET. In comparison to table 3, the examples shown in table 4 show the effect of varying the PTT to co-PET blend ratio in the first component while maintaining a constant 50/50 weight ratio between the two components. In Table 4, examples 4a through 4D and examples 4f through 4g and comparative example D were prepared by varying the particle ratios in the "salt and pepper blend" ("S & P") of 0.96IV dl/g PTT and 0.82IV dl/g co-PET. The particles were mixed together until randomly dispersed. After drying, the pellet mixture was fed into a West extruder. The dried 0.50IV PET homopolymer pellets were fed to an East extruder. Bicomponent fibers were then prepared with a first component comprising the PTT/co-PET blend described above and a second member comprising PET, with the weight ratio between the two members fixed at 50/50. For example, in example 4a, the first component of the bicomponent was made of 10/90 blend ratio of PTT/co-PET and the second component of the bicomponent was made of PET. The weight ratio between the two components was 50/50. In example 4-e, PTT and co-PET pellets were pre-compounded in a twin screw extruder, quenched, pelletized, and re-dried prior to use. This is in contrast to example 4d, where the components were made from a salt and pepper blend. It should also be noted that comparative example D contains a higher post-heat crimp contraction value,% CCa ═ 43.1, more suitable for high stretch levels in apparel fabrics.

For example 4-a, the winder speed was 3475 m/min; for examples 4-b, 4-c, 4-D, 4-e, 4-f, 4-g and comparative example D, the winder speed was 3500 m/min.

TABLE 4 Process conditions and crimp contraction for examples 4a through 4g and comparative example D

Example 5

Carpet production Using self-expanding bicomponent fibers as in example 2a

Carpets comprising self-bulking bicomponent fibers can be spun at 1200 denier to 120 filaments (10dpf) using the polymers, polymer IV and fiber weight ratios described in example 2a above. These bicomponent fibers will have higher denier and filament count than example 2 a. The spinning speed (i.e., draw ratio) will be adjusted so that the resulting fiber has a crimp contraction after heating of 30% or less. The bicomponent fiber so produced can be plied with a second bicomponent fiber of the same type on standard twisting equipment. After twisting, can pass through

The fibers are processed by a sizing device that will fully develop the bicomponent fiber crimp and set the twist in the plied yarn. The heat-set bicomponent yarn can then be tufted into a nonwoven polypropylene backing on a standard carpet tufting machine along with other heat-set yarns of the same composition to give a tufted fabric consisting entirely of heat-set, plied bicomponent yarns. The tufted fabric can then be processed on standard processing equipment used in the carpet industry to process the tufted fabricA latex formulation is applied to the back of the carpet that locks the tufted face fibers into the woven carpet backing. A secondary backing would then be applied to protect the underside of the carpet. The greige (undried) carpet can be processed on standard continuous dyeing equipment and then dried in a continuous oven to remove moisture. The finished carpet is then rolled onto a large tube for installation on site.

Example 6

Carpet production Using self-expanding bicomponent fibers as in example 2a

Carpets comprising self-bulking bicomponent fibers can be spun at 1200 denier to 120 filaments (10dpf) using the polymers, polymer IV and fiber weight ratios described in example 2a above. The spinneret orifices are selected to produce a side-by-side trilobal cross-section, although any other cross-sectional shape useful for carpet manufacture may be selected. These bicomponent fibers would have higher denier and filament count and trilobal cross-sectional shape than example 2 a. The spinning speed (i.e., draw ratio) will be adjusted so that the resulting fiber has a crimp contraction after heating of 30% or less. The bicomponent fiber so produced can be plied with a second bicomponent fiber of the same type on standard twisting equipment. After twisting, can pass through

The fibers are processed by a heat-setting apparatus that will develop sufficient bicomponent fiber crimp and set the twist in the plied yarns. The heat-set bicomponent yarn can then be tufted into a nonwoven polypropylene backing on a standard carpet tufting machine along with other heat-set yarns of the same composition to give a tufted fabric consisting entirely of heat-set, plied bicomponent yarns. The tufted fabric can then be processed on standard processing equipment used in the carpet industry to apply a latex formulation to the back of the carpet that locks the tufted face fibers in the woven carpet backing. A secondary backing would then be applied to protect the underside of the carpet. The greige (undried) carpet can be processed on standard continuous dyeing equipment, and thenAnd then dried in a continuous oven to remove moisture. The finished carpet is then rolled onto a large tube for field installation.

Claims

1. A carpet having face fibers comprising bicomponent fibers comprising one component of poly (ethylene terephthalate) homopolymer or poly (ethylene terephthalate) copolymer and a second component of poly (trimethylene terephthalate) or a blend of poly (trimethylene terephthalate) and poly (ethylene terephthalate) homopolymer or poly (ethylene terephthalate) copolymer, wherein the bicomponent fibers are self-bulking due to differential shrinkage as compared to carpets having face fibers made from mechanically bulked continuous monocomponent filaments.

2. The carpet of claim 1, wherein the bicomponent fiber may be in a side-by-side configuration or an eccentric sheath-core configuration.

3. The carpet of claim 1 or claim 2, wherein the first and second components of the bicomponent fiber are present in a weight ratio of from 80: 20 to 20: 80.

4. The carpet of claim 1 or claim 2, wherein the bicomponent fiber has a post-heating crimp contraction of equal to or less than 30% as determined by the crimp contraction method.

5. The carpet of claim 3, wherein the bicomponent fiber has a post-heating crimp contraction of equal to or less than 30% as determined by the crimp contraction method.

6. The carpet of claim 1, wherein the face fibers further comprise at least one additional fiber selected from the group consisting of: bulked continuous filament, synthetic staple, and natural fibers.

7. The carpet of claim 6, wherein the at least one additional fiber is bulked continuous filament and the bulked continuous filament comprises nylon, polypropylene, or polyester.

8. The carpet of claim 6, wherein the at least one additional fiber is a synthetic staple fiber and the synthetic staple fiber comprises nylon or polyester.

9. The carpet of claim 6, wherein the at least one additional fiber is a natural fiber and the natural fiber comprises wool, silk, or cotton.

10. An improved process for making a yarn to produce a carpet having face fibers comprising a self-bulking bicomponent fiber comprising one component of a poly (ethylene terephthalate) homopolymer or poly (ethylene terephthalate) copolymer and a second component of a blend of poly (trimethylene terephthalate) or poly (trimethylene terephthalate) and poly (ethylene terephthalate) homopolymer or poly (ethylene terephthalate) copolymer,

the method comprises the following steps:

c) quenching the self-bulking bicomponent fibers produced in step (b) in air;

d) stretching and heat-setting the self-expandable bicomponent fibers; and

e) winding the self-bulking bicomponent fiber by suitable means for subsequent processing into a carpet,

wherein the self-bulking bicomponent fiber eliminates the need for a mechanical bulking step.

11. The improved process of claim 10 wherein said bicomponent fibers may be in a side-by-side configuration or an eccentric sheath-core configuration.

12. The improved process of claim 10 or 11, wherein the first and second components of the bicomponent fiber are present in a weight ratio of 80: 20 to 20: 80.

13. The improved process of claim 10 or claim 11 wherein the bicomponent fiber has a post-heating crimp contraction of 30% or less as determined by the crimp contraction method.

14. The improved process of claim 12 wherein said bicomponent fiber has a post-heating crimp contraction of 30% or less as determined by the crimp contraction process.